"Nadella would be very smart to organize a 100-day plan. That would be brilliant," said Randy Ottinger, an executive vice president with Kotter International, a Cambridge Mass. consultancy that specializes in leadership change and setting corporate strategy. "No question that there's a first 100 days for a new CEO."

Dallying won't do.

Ottinger said it's crucial for a new CEO, even one who has, like Nadella, spent decades inside a company, to strike hard, strike fast, with a pre-planned and fast-moving program akin to those that U.S. presidents have relied on to set their administrations' political tone and agenda.

Franklin D. Roosevelt's first 100 days, when he pushed major pieces of his New Deal through Congress, have become a benchmark by which later presidents have been measured. It's the same in the corporate equivalent of the Oval Office, said Ottinger. While the early agenda may not be visible from the outside, as would a politician's, it should exist.

"Who's on my leadership team, who is my cabinet? Who am I betting on to shape the future of the company?" asked Ottinger, citing an example of what should occupy the chief executive's time.

Although Nadella is a 22-year Microsoft veteran and the head of its cloud-computing and server software division -- which generated more than $19 billion in revenue last year -- he has been portrayed as green because he lacks CEO experience, much less at a firm of Microsoft's size. That makes it even more important that he have a 100-day program.

Speed plays a part, one of the reasons why 100-day programs, whether in politics or corporate leadership, continue to be used. "A new CEO must create a sense of urgency," said Ottinger.

Nadella's to-do list should look something like this.

"First, what is the big opportunity in the market? Where is Microsoft going to play? What are you going to bet on and what are you going to cut?" said Ottinger. "Two, the leadership team, who is on it? Three, the board. Who is adding value? Are they aligned with the vision we're going for now? Four, the alignment on that opportunity and creating urgency. That leads to engagement with all employees, which leads to financial results."

A new CEO, even one from inside a company, typically purges at least part of the current leadership team, the senior executives who report directly to the chief executive, said Ottinger, who expects Nadella to do the same at Microsoft. A move like that would make the team his rather than accept a group that were, after all, beholden to Ballmer for their jobs.

Sticking with the people now in the top spots -- like COO Kevin Turner or Terry Myerson, who leads operating system development -- would be akin to a new president keeping his predecessor's cabinet intact. That's been done, but only in extreme cases, such as when FDR and JFK died in office and Harry Truman and Lyndon Johnson stepped in.